Dual mode smart card and associated methods

ABSTRACT

A dual-mode IC is provided for operating in first mode such as an ISO mode in accordance with International Standards Organization 7816 (ISO 7816) protocol, and a second, non-ISO mode, such as a USB mode in accordance with Universal Serial Bus (USB) protocol. The dual-mode IC is preferably in a smart card and includes a microprocessor, a switching block, and an external interface. The external interface includes a voltage supply pad, a reference voltage pad, a reset pad, a clock pad and an input/output pad in accordance with the ISO 7816 protocol, and a D-plus pad and D-minus pad in accordance with the USB protocol. The IC further includes a mode configuration circuit for detecting a USB mode condition on at least one of the D-plus and D-minus pads, and configuring the IC in the ISO mode or the USB mode depending on the result. Once the IC is configured in a particular mode, it will operate in only that mode until the next power-on reset sequence.

FIELD OF THE INVENTION

The present invention relates to information processing and storage, andmore particularly, to smart card systems using various protocols.

BACKGROUND OF THE INVENTION

Smart cards SC are plastic cards having an embedded Integrated Circuit(IC). That IC may be a logic circuit with its associated memories or amicrocontroller with its associated memories and software, or amicrocontroller with its associated memories and software coupled to acustom block.

To use the computing power given by the IC, a SC makes use of a full setof packaging technologies. The die size varies from 1 mm² to 30 mm². Thedie size is limited for mechanical aspects going with the plastic natureof the SC. The IC is attached to a lead frame and wire-bondingtechniques are used to connect the IC pads to the lead frame contacts.Potting and other strengthening methods protect the IC against chemicaland mechanical stresses. Contacts are located on one side of the cardand their number is limited to eight. Ultimately SC performstransactions with a SC reader using a serial protocol. All themechanical and electrical specifications of SC are published by theInternational Standard Organization (ISO). The ISO7816-X standards haveallowed the simple and massively produced magnetic stripe cards toevolve toward the SC. SC, depending of the IC complexity, may performpre-paid accounting, cryptographic scheme, personal authentication usingPIN code or biometrics and run java scripts to name few.

ISO documents ISO 7816-1 Physical Characteristics, ISO 7816-2 Dimensionsand Locations of the contacts, ISO 7816-3 Electronic signals andtransmission protocols and, ISO 7816-10 Electronic signals and answer toreset for synchronous cards are incorporated herein by reference.

Today all the SC readers have to be recognized by the infrastructureprior to perform any transaction involving a SC. The infrastructure isrunning an application in which the SC end is involved. The SC readerexpects a SC. The half duplex protocol between the SC and the SC reader,in which, either the SC sends information to the SC reader or viceversa, cannot start until a SC is detected in place into the SC reader.The infrastructure manages authentication or transactions for pre-paidcards in public telephony, for Bank cards in Point Of Sale (POS)terminals and Automatic Teller Machines (ATM), for Pay TV providers inset top boxes and for wireless telecom operators in SubscriberIdentification Modules (SIM) in Global System for Mobile (GSM)terminals. Except for SIM cards, all others applications use a physicalsensor to detect the SC. This sensor tells the SC reader when a SC is inplace that is when the SC lead frame contacts are able to mate with theSC reader contacts. Two sorts of SC reader contacts can be used,contacts that remain in place and because of their elasticity can slideover the SC when inserted in the SC reader or mobile contacts whichdescend to touch the lead frame contacts once the card has been detectedin place. When the SC reader has established that a SC is in place thepower up sequence can start at the SC reader convenience. After thepower up sequence, the SC reader will provide first a clock to the SCand then will release its reset signal. The SC is then able to executethe stored Operating System (OS). The SIM card is particular since it isput in place only once with the power off and used constantly.

The first application ever to have deployed the SC technology more than20 years ago is the public telephone system. The die size used in thisapplication is less than 1 mm². Just memories and logic circuits areintegrated in the IC. In 1999, Pre-paid SC accounted for more than ⅔ ofthe millions SC produced worldwide. The SC reader utilizes all eightcontacts to interface properly with the different SC generations. When aSC is inserted in the payphone, the telephone infrastructureauthenticates the SC and the telephone remove units out of the SC. It isworth noting that the SC developed for Banking applications can beutilized in a payphone. The payphone does not remove units out of a Bankcard but bills the SC carrier.

The second largest application using the SC has been deployed by theBanking industry. The ATM and POS infrastructures have been installed inmost countries other than the USA. The die size used in this applicationis about 10 mm². A microcontroller and its associated memories andsoftware are integrated in the IC. The SC reader utilizes up to sixcontacts to interface properly with the different SC generations. When aSC is inserted in the ATM or the POS, the SC carrier is asked toauthenticate himself with a PIN code. The SC can store anything like thebalance of cash the owner got out of an ATM on a per week basis, thedetails of purchases he has done since the last closing date, etc. Basedon this information, the authorization can be issued on the spot oncethe PIN has authenticated the debtor without any telephone calls to thebank. Ultimately Banks and Businesses perform the equalization using thetelephone, private communication networks and some day the Internet.While performing the equalization, a black list of fraudulent SC may bestored in the POS or ATM. This scheme has been able to reduce the fraudlevel down to 0.02% of all the transactions equivalent money done withthe SC from 0.2% when no IC was embedded in the card. The level of fraudusing SC has been reduced by ten fold compared to the regular creditcards.

The third largest application using SCs has been deployed by GSMmanufacturer. The die size used in a SIM is about 30 mm². Amicrocontroller and its associated memories and software are integratedin the IC. The SIM reader utilizes five contacts to interface properlywith the SC. The most sophisticated SC applications are performed in GSMusing Java applets.

A whole new market for the SC is now emerging with the Internet accessedfrom a Personnel Computer. Secure message, Public Key Infrastructure,Authentication and Electronic Payment are the new SC hot areas. The SCcan be an e-commerce facilitator. The differentiation of the smartcardcompared to other solutions is to have the PIN in the memory that isnever communicated in any transaction.

Up to now, the SC is used in a SC reader connected to the computer. Twoprotocols are involved in supporting transactions between the SC and theapplication run by the computer. The first protocol complies with theISO-7816-3. This standard provides detailed requirements for the serialinterface between SC and SC reader. The reader is connected to thecomputer by via a Serial Port, a Parallel Port or even the UniversalSerial Bus (USB) using a second protocol. The SC reader containselectronic circuits and embedded software that enable communicationbetween the SC using the first protocol and the computer using thesecond protocol. The computer is loaded with the appropriate driver tosupport the SC reader. Many countries have started to use the SC in thePC environment. The die size used in this application will be anywherefrom 5 mm² to 30 mm². A microcontroller and its associated memories andsoftware are integrated in the IC with a cryptocontroller. Sometimes, abio-sensor will be also integrated. The SC reader utilizes at least fivecontacts to interface properly with the SC.

Closed infrastructures enabling all kinds of transactions likeHealthcare, Public phone, parking, Loyalty programs, Cash payments,Credit payments are using millions of ISO compliant SC readers aroundthe world. Europe has lead the development of these technologies back inthe late 1970's. In these proprietary infrastructures, every single SCreader is designed to carry many transactions each hour. The many usersshare the cost of the SC reader.

The extreme growths of the e-commerce and Internet transactions havehighlighted the huge needs to secure transactions. Fraud is booming.False credit card numbers are used, credit card numbers are stolen andeavesdropping on the Internet is well established. Dotcom companiessearch for the device having the best cost/performance ratio. The SC isan excellent contender if the SC reader price can be reduced.

The USB has recently become firmly established and has gained wideacceptance in the Personal Computer (PC) marketplace. The USB has beendeveloped in response to a need for a standard interface that extendsthe concept of “plug and play” to devices external to a PC. It hasenabled users to install and remove external peripheral devices withouthaving to open the PC case or to remove power from the PC. The USBprovides a low-cost, high performances, half-duplex serial interfacethat is easy to use and readily expandable. The USB can be seen as a setof four wires carrying the supply power with two wires and data with thetwo other wires. The USB is currently defined by the Universal SerialBus Specification written and controlled by USB Implementers Forum,Inc., a non-profit corporation founded by the group of companies thatdeveloped the USB Specification.

In particular, Chapter 5 USB Data Flow Model, Chapter 7 Electrical,Chapter 8 Protocol Layer and Chapter 9 USB Device Framework of UniversalSerial Bus Specification are incorporated herein by reference. Theincreasingly widespread use of the USB in computers has led SC readermanufacturers to develop USB interfaces for connection of their productsto computers to complement the existing serial and parallel interfaces.

We are now in a situation where the brick and mortar companies and theBanks have been using the SC technology for more than 25 years. On theother hand, the Internet, a formidable arena to enhance commerce andBanking activities, does not use the SC technology. Most of the Internettransactions are done from a PC and despite PC manufacturer efforts, thePC industry has failed to install on each PC a cost effective SC readermeeting the specific needs of web related applications. A comprehensivesolution, servicing the needs of both the one already engaged in the SCtechnologies and those wishing to benefit from it, is to be found. Thesetwo fields should share a common authentication platform in the bestinterests of the customers and the service providers.

An example of a conventional approach may be found in published PCTapplication WO 99/49415 and entitled “Versatile Interface Smart Card.”The system discloses a smart card system which can be used withdifferent protocols. Specifically, the system provides a mode signal atone of the non-ISO standard contacts to indicate the protocol of thedevice that the card is communicating with. However, the mode signal isnot checked until after the smart card is powered up and the resetsignal has been applied. In other words, the smart card is alreadyoperating in the ISO 7816 protocol, and upon detection of the modesignal, may have to switch to a non-ISO protocol.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of theinvention to provide an integrated circuit which can operate accordingto more than one protocol.

It is a further object of the invention to provide a smart card systemthat can determine whether the smart card is communicating with a deviceusing the ISO 7816 protocol or the USB protocol, and configure the smartcard in such a protocol.

This and other objects, features and advantages in accordance with afirst embodiment of the present invention are provided by a dual-mode ICfor operating in first mode such as an ISO mode in accordance withInternational Standards Organization 7816 (ISO 7816) protocol, and a USBmode in accordance with Universal Serial Bus (USB) protocol. Thedual-mode IC is preferably in a smart card and includes amicroprocessor, a switching block, and an external interface. Theexternal interface comprises a voltage supply pad, a ground or referencevoltage pad, a first set of pads for the first mode, and a second set ofpads for the USB mode. The first set of pads preferably include a resetpad, a clock pad and an input/output pad in accordance with the ISO 7816protocol, and the second set of pads preferably includes a D-plus padand a D-minus pad in accordance with the USB protocol. The IC furtherincludes a mode configuration circuit comprising a USB mode detectorconnected to at least one of the D-plus and D-minus pads. A pull-upresistor may be connected to one of the D-plus and D-minus pads, and aUSB voltage detector may be connected to the voltage supply pad. Alatching circuit is connected between the switching block and the USBmode detector, and a control register may be connected to the latchingcircuit for storing a mode configuration indicator.

The mode configuration circuit preferably configures the IC to operatein one of the ISO and USB modes while disabling the other of the ISO andUSB modes. As such, the reset, clock and input/output pads are disabledwhen the IC is configured in the USB mode, and the D-plus and D-minuspads are disabled when the IC is configured in the ISO mode. Preferably,in the first embodiment, the mode configuration circuit configures theIC to operate in the ISO mode as a default if the USB mode detector doesnot detect the USB mode. However, in a second embodiment, an ISOdetector is provided for detecting an ISO-mode condition. Here, the modeconfiguration circuit configures the IC in the mode detected by the USBdetector or the ISO detector.

The USB mode detector may detect if a low speed USB device is connectedto the D-plus and D-minus pads, and the USB voltage detector may detectwhether a power supply on the voltage supply pad is greater than about3.5 volts or preferably between about 4.01 and 5.5 volts. The ISO-modedetector may detect the rising of a signal on the reset pad as theISO-mode condition. Of course, to ensure that the ISO- mode is detected,the ISO-protocol sequence may be detected via the reset, clock and I/Opads.

A method aspect of the present invention is directed to a method ofoperating a dual-mode IC in an ISO-mode in accordance with the ISOprotocol, and a USB-mode in accordance with the USB protocol. Thedual-mode IC includes an external interface having a voltage supply pad,a first set of pads in accordance with the ISO protocol, and a secondset of pads in accordance with the USB protocol. The method includesdetecting whether a USB-mode condition exists on at least one pad of thesecond set of pads during a power-on-reset of the dual-mode IC. Themethod may also include verifying the USB-mode, when the USB-modecondition is detected, by detecting a USB-mode voltage on the voltagesupply pad.

The dual-mode IC is configured in the USB mode and the first set of padsis disabled upon verification of the USB mode voltage. Also, accordingto the first embodiment, the method includes configuring the dual-modeIC in the ISO mode and disabling the second set of pads when theUSB-mode condition is not detected. However, in accordance with thesecond embodiment, the method includes detecting whether an ISO-modecondition exists on one pad of the first set of pads. Here, the methodincludes configuring the dual-mode IC in the ISO mode and disabling thesecond set of pads when the ISO-mode condition is detected.

The first set of pads comprises a reset pad, a clock pad and aninput/output pad in accordance with the ISO 7816 protocol. Also, thesecond set of pads comprises a D-plus pad and a D-minus pad inaccordance with the USB protocol. Detecting whether the USB-modecondition exists may comprise detecting whether the second set of padsare connected to a USB device. Again, verifying the second mode maycomprise detecting whether a power supply on the voltage supply pad isgreater than about 3.5 volts, or preferably between about 4.1 and 5.5volts. Furthermore, the method includes storing a mode configurationindicator for indicating whether the dual-mode IC is configured in theISO or USB mode.

In the first embodiment, the IC is configured in the ISO mode by defaultif the USB mode is not detected on the second set of pads, such as theD-plus and D-minus pads. If a USB device is detected via the D-plus andD-minus pads during the power-on reset sequence, then the IC USB voltageis verified on the voltage supply pad before the IC is configured in theUSB mode. Once the IC is configured in one mode, it can only operate inthat mode and it cannot be changed except via another power-on resetsequence.

In the second embodiment, the IC is configured in the ISO mode if an ISOcondition is detected on one of the first pads, such as the reset pad.Similar to the first embodiment, if a USB device is detected via theD-plus and D-minus pads during the power-on reset sequence, then the USBvoltage is verified on the voltage supply pad before the IC isconfigured in the USB mode. However, unlike the first embodiment, thedefault is a neutral mode where the IC is not configured in either theISO or USB mode. Once the IC is configured in one mode, it can onlyoperate in that mode and it cannot be changed except via anotherpower-on reset sequence.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a smart card according to the presentinvention.

FIG. 2 is a schematic diagram of a personal computer having a smart cardreader in accordance with the present invention.

FIG. 3 is a schematic diagram of a dual-mode IC according to a firstembodiment of the present invention.

FIG. 4 is a flowchart generally illustrating the steps of a method ofoperating the dual mode IC of the first embodiment.

FIG. 5 is a schematic diagram of a dual-mode IC according to a secondembodiment of the present invention.

FIG. 6 is a flowchart generally illustrating the steps of a method ofoperating the dual mode IC of the second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

Referring to FIG. 1, a smart card 10 in accordance with the presentinvention will now be described. The smart card 10 is made of plastic,for example, and has a plurality of electrical contacts or pads 12 on anouter surface thereof, as would be appreciated by those skilled in theart. As shown, the card 10 includes eight pads 12, for example. The pads12 are the external interface for the integrated circuit (IC) 11 whichis embedded within the card 10 and typically beneath the pads. The sizeof the card 10 and the position of the pads 12 are determined byappropriate standards such as the ISO 7816 protocol discussed above. Ofcourse the IC 11 can also be embedded in other media such as theSubscriber Identity Module (SIM) for mobile phones, a token or otherwireless USB device.

A personal computer (PC) 20, as shown in FIG. 2, typically includes acentral processing unit (CPU) and various input/output devices such as amonitor, keyboard and a mouse. Additionally, the PC 20 includes a smartcard reader 22 which may, for example, be used to control access to thePC. As shown, the smart card reader 22 is a separate peripheral device;however, the smart card reader could also be incorporated into the CPUhousing or the keyboard, for example.

The smart card reader 22 may conform to the ISO 7816 protocol or anon-ISO protocol such as the Universal Serial Bus (USB) protocol asdiscussed above. The ISO 7816 protocol is the conventional standard foruse in smart cards and includes a voltage supply pad VCC, a ground padGND, an input/output pad I/O, a reset pad RST and a clock pad CLK. TheISO protocol is characterized by an Answer-to-Reset (ATR) sequence whena power-on-reset or hardware reset is applied to the IC 11.

The USB protocol is currently being used to replace the different PC 20interfaces for peripheral devices such as the mouse, keyboard, serialI/O port etc. The USB protocol can be hot plug and play which means thata USB protocol device can be connected or disconnected from the PC 20without necessitating a reboot. The USB cable includes a voltage supplywire VBUS, a ground wire GND, a D-plus wire DP and a D-minus wire DM.The signal on DP and DM is a data stream in NRZI coding and includes theclock. The USB 1.1 specification requires the power supply of a USBdevice to be between 4.01V and 5.5V.

As set forth previously, it is desirable to provide a smart card systemthat can operate in the ISO 7816 protocol and another non-ISO protocol,such as the USB protocol, depending on the type of reader the card iscommunicating with. Thus, referring to FIG. 3, a first embodiment of thepresent invention will be described. A dual-mode IC 11 is capable ofoperating in first mode such as an ISO mode in accordance withInternational Standards Organization 7816 (ISO 7816) protocol, and asecond non-ISO mode such as a USB mode in accordance with UniversalSerial Bus (USB) protocol. The dual-mode IC 11 operates selectively inone mode or the other, but not both simultaneously.

The dual-mode IC 11 is preferably in the smart card 10 and includes amicroprocessor 14, a switching block 16, and the external interface 12.The external interface 12 comprises a voltage supply pad VCC, areference voltage/ground pad GND, a first set of pads for the ISO mode,and a second set of pads for the non-ISO mode. The first set of padspreferably include a reset pad RST, a clock pad CLK and an input/outputI/O pad in accordance with the ISO 7816 protocol. The second set of padspreferably includes a D-plus pad DP and a D-minus pad DM in accordancewith the USB protocol.

Because the IC 11 can only operate in one of the two modes which havedifferent external interfaces, the IC will need to determine in whichmode to operate. Thus, the IC 11 includes a mode configuration circuit18 comprising a USB mode detector 34 connected to at least the D-minuspad.

The USB mode detector may also be connected to the D-plus DP pad asshown in FIG. 3. The mode configuration circuit 18 may also include aUSB voltage detector 30 connected to the voltage supply pad VCC fordetecting a USB mode voltage supply, a latching circuit 40 connected tothe switching block and receiving outputs from the USB mode detector 34and the USB voltage detector 30, and a control register 42 connected tothe latching circuit 40 for storing a mode configuration indicator.

A delay block 36 may be connected between the USB mode detector 34 andthe latching circuit 40, while a power-on-reset circuit may be connectedbetween the voltage supply pad VCC and the buffer. The delay block 36delays the detection by the USB mode detector 34 until a predeterminedtime, e.g. 1-10 ms, after first contact to avoid a false detection dueto rebound. Also, a logic gate/circuit 38 may be connected between thelatching circuit 40 and the detectors 30, 34. Furthermore, the USB 1.1protocol requires a 1.5 KOhm resistor 44 connected between the D-minuspad DM and about 3.6V or VTERM from a voltage regulator to aid in theidentification of a low-speed USB device, as would be appreciated by theskilled artisan.

During the start-up or power-on sequence of the IC 11, the modeconfiguration circuit 18 configures the IC 11 to operate in one of theISO and USB modes while disabling the other mode. For example, the resetpad RST, clock pad CLK and input/output I/O pad are disabled when the IC11 is configured in the USB mode, and the D-plus pad DP and D-minus DMpad are disabled when the IC 11 is configured in the ISO mode. Toprevent any glitches, the detected mode is latched by the latchingcircuit 40 while the appropriate bit is set in the control register 42.Because the mode detection is a hardware detection, the operating systemof the IC 11 will then check this bit during the reset routine to accessthe appropriate code for the latched mode.

Accordingly, if the smart card 10 including the dual mode IC 11 is usedwith a typical smart card reader, it will operate as specified in theISO 7816 protocol while the USB interface, i.e. the D-plus DP andD-minus DM pads, is disabled to consume less power. However, because theIC 11 includes a USB interface, ISO 7816-like transactions can beperformed using a low-cost USB device rather than an ISO-compliant smartcard reader. Here, the ISO mode interface, i.e. the reset RST, clock CLKand input/output I/O pads, is disabled. Once the IC 11 is configured inone of the modes, it must stay in that mode until anotherpower-on-reset.

For security and integrity of the dual-mode IC 11, the mode should bedetected as soon as possible because once the IC is configured in amode, it will not be changed until another power-on-reset is executed.In this embodiment, the IC 11 is configurable in the ISO mode bydefault. In other words, if the USB mode is not detected, then the modeconfiguration circuit 18 configures the IC 11 in the ISO mode anddisables the USB mode and interface. To operate in the USB mode, thepresence of a USB bus must be detected before an ATR of ISO 7816 occurs.In the USB protocol, a low-speed USB device is detected with a pull-upresistor, such as resistor 44, on DM. A downstream transceiver of a USBhub has a pull-down resistor connectable to the D-plus DP and D-minuspads DM. So, when the IC 11 is connected to a USB hub, a current wouldbe sensed by the USB device and the IC 11 would be recognized as beinglow-speed on DM and/or high-speed on DP.

When the IC 11 is powered by the USB device when it is attached, thepower-on-reset signal will reset the IC 11 when it reaches 2.3V. Thissignal stays at “1” until a DC/DC voltage regulator of the IC 11 isstable, e.g. for about 300 μs. When the power-on-reset signal falls to“0”, it means the IC 11 supply is greater than 2.3V and the DC/DC isstable. The USB mode detector should be powered by the same voltageregulator as the IC 11 to be active as soon as possible. At power-on,the pull up resistor 44 on D-minus DM is not active until the voltageregulator (VTERM) is turned on by the IC 11. The microprocessor 14 readsthe control register 42 for the indication of the mode in which tooperate. For the USB mode, the microprocessor 14 starts the voltageregulator of the USB protocol. In this condition, the two pull downresistors of the USB hub which are now connected to the D-plus DP andD-minus DM pads, create a “0” state on the bus of the USB device. Thetrailing edge of the power-on-reset signal can create a pulse of 1 msvia delay block 36 during which the mode configuration circuit willdetect the USB mode. However, this time can be increased, e.g. to 10 ms,if it is necessary to ensure that it works accurately during a slowinsertion of the medium, e.g. the smart card 10, in the USB reader.

Thus, preferably, the USB mode detector 34 detects the “0” state on theD-plus and D-minus pads when the power-on-reset signal falls to “0”. Ifso, then the USB voltage detector 30 detects whether a power supply onthe voltage supply pad VCC is greater than about 3.5 volts or preferablybetween about 4.01 and 5.5 volts to verify that the medium with thedual-mode IC 11 is communicating with a USB device.

So, in sum, for ISO mode, the mode configuration circuit 18 sets theswitching block 16 in ISO mode which starts the IC 11 in the ISO mode.The USB pads DP, DM and the mode configuration circuit 18 may then bedisabled. For the USB mode, the mode configuration circuit 18 sets theswitching block 16 in USB mode which starts the IC 11 in the USB mode.The microprocessor 14 verifies that there is a USB cable attached andthen enables the voltage regulator providing VTERM to the DM pad viaresistor 44. The mode configuration circuit 18 and the ISO pads may thenbe disabled.

A system using such an IC 11 in accordance with the present inventionincludes a ISO-compliant reader and a USB-compliant reader. TheISO-protocol reader may be a conventional smart card reader that wouldprovide the necessary signals at the appropriate pads of the externalinterface 12 of the IC 11 as would be appreciated by the skilledartisan. Thus, when a smart card 10 including the dual mode IC 11 isinserted into a conventional smart card reader, the mode configurationcircuit 18 configures the IC 11 in the ISO mode because the USB-modecondition is not detected on the D-plus and D-minus pads. However, aUSB-compliant reader would create the USB-mode condition on the D-plusand D-minus pads. So, when the smart card 10, or other medium, isconnected to such a USB-compliant reader, the mode configuration circuit18 configures the IC 11 in the USB mode because the USB-mode conditionis detected.

A method aspect of the first embodiment of the present invention willnow be discussed while referring to FIG. 4. The method includesoperating a dual-protocol smart card 10 in a first mode in accordancewith an ISO protocol, and a second mode in accordance with a non-ISOprotocol, such as the USB protocol. As discussed above, thedual-protocol smart card 10 includes an external interface 12 having avoltage supply pad VCC, a reference voltage/ground pad GND, a first setof pads CLK, RST, I/O in accordance with the ISO protocol, and a secondset of pads, e.g. DP, DM, in accordance with the non-ISO protocol suchas USB.

The method begins (block 80) and a power-on-reset sequence of the IC 11is started at block 82. Then, at block 84, the method includes detectingwhether a USB-mode condition exists on at least one of the DM and DPpads during the power-on-reset of the dual-mode IC. For security andintegrity of the IC 11, the mode should be detected as soon as possiblebecause once the IC is configured in a mode, it will not be changeduntil another power-on-reset is executed. In this embodiment, the IC 11is configurable in the ISO mode by default. In other words, if the USBmode is not detected at block 84, then the IC 11 is configured in theISO mode and the USB mode and interface are disabled (block 90) byconnecting the DP and DM pads to GND, for example. Alternatively, if theUSB-mode condition is detected at block 84, then the IC 11 is configuredin the USB mode, and the first set of pads, i.e. CLK, RST, I/O, inaccordance with the ISO protocol is disabled (block 88) by connectingthem to GND, for example.

The method may include verifying the USB mode, when the USB-modecondition is detected at block 84, by detecting a USB-mode voltage onthe voltage supply pad VCC (block 86). The method may include storing amode configuration indicator for indicating whether the dual-mode IC isconfigured in the ISO or USB mode (block 92) before ending at block 94.

For example, the IC 11 is configured in the ISO mode if a USB-modecondition detected is not detected on the at least the DM pad.Preferably, if a USB device is detected via the DM or DP pads during thepower-on reset sequence, then a USB voltage is verified on the voltagesupply pad VCC before the IC 11 is configured in the USB mode. Once theIC 11 is configured in one mode, it can only operate in that mode and itcannot be changed except via another power-on-reset sequence. To preventany glitches, the detected mode is preferably latched and a modeconfiguration indicator/bit is set. The operating system of the IC 11will then check this bit during the reset routine to access theappropriate code for the latched mode.

A second embodiment of the present invention will now be described whilereferring to FIGS. 5 and 6. The second embodiment of the dual-mode IC 51is substantially similar to the first embodiment dual-mode IC 11 excepthere the mode configuration circuit 58 includes an ISO-mode detector 48connected between the latching circuit 40 and the reset pad RST of theexternal interface 12. Specifically, instead of the mode configurationcircuit 58 configuring the IC 51 in an ISO mode by default when aUSB-mode condition is not detected, a detection for an ISO-modecondition will be performed before the mode configuration circuit 58will configure the IC 51.

The advantage of this embodiment is the avoidance of a erroneousdetection of the non-selected mode during the time the IC 51 is beingconfigured and the mode configuration indicator/bit is being read by themicroprocessor 14. The ISO-mode condition that is detected is preferablythe rising of the signal on the reset pad RST from a low to a highlevel. Again, preferably, if the USB mode detector 34 detects the “0”state on the D-plus and D-minus pads when the power-on-reset signalfalls to “0”, then the USB voltage detector 30 detects whether a powersupply on the voltage supply pad VCC is greater than about 3.5 volts orpreferably between about 4.01 and 5.5 volts to verify that the mediumwith the dual-mode IC 51 is communicating with a USB device.

A method aspect of the second embodiment of the present invention willnow be discussed while referring to FIG. 6. The method includesoperating a dual-protocol smart card 10 in a first mode in accordancewith an ISO protocol, and a second mode in accordance with a non-ISOprotocol, such as the USB protocol. As discussed above, thedual-protocol smart card 10 includes an external interface 12 having avoltage supply pad VCC, a reference voltage/ground pad GND, a first setof pads CLK, RST, I/O in accordance with the ISO protocol, and a secondset of pads, e.g. DP, DM, in accordance with the non-ISO protocol suchas USB.

The method begins (block 100) and a power-on-reset sequence of the IC 51is started at block 102. Then, at block 104, the method includesdetecting whether a USB-mode condition exists on at least one of the DMand DP pads or whether an ISO-mode condition exists on one of the firstset of pads, such as the reset pad RST, during the power-on-reset of thedual-mode IC 51. Again, for security and integrity of the IC 51, themode should be detected as soon as possible because once the IC isconfigured in a mode, it will not be changed until anotherpower-on-reset is executed. In this embodiment, the IC 51 isconfigurable in the ISO mode if an ISO-mode condition is detected. Ifso, then the IC 51 is configured in the ISO mode and the USB mode andinterface are disabled (block 110) by connecting the DP and DM pads toGND, for example. Alternatively, if the USB-mode condition is detectedat block 104, then the IC 51 is configured in the USB mode, and thefirst set of pads, i.e. CLK, RST, I/O, in accordance with the ISOprotocol is disabled (block 108) by connecting them to GND, for example.

As in the first embodiment, the method may include verifying the USBmode, when the USB-mode condition is detected at block 104, by detectinga USB-mode voltage on the voltage supply pad VCC (block 106). Also, themethod may include storing a mode configuration indicator for indicatingto the microprocessor whether the dual-mode IC is configured in the ISOor USB mode (block 112) before ending at block 114.

For example, the IC 51 is configured in the ISO mode if a ISO-modecondition is detected on the reset pad RST. Preferably, if a USB deviceis detected via the DM or DP pads during the power-on reset sequence,then a USB voltage is verified on the voltage supply pad VCC before theIC 51 is configured in the USB mode. As discussed previously, once theIC 51 is configured in one mode, it can only operate in that mode and itcannot be changed except via another power-on-reset sequence. To preventany glitches, e.g. a mode change, the detected mode is preferablylatched and a mode configuration indicator/bit is set. The operatingsystem of the IC 51 will then check this bit during the reset routine toaccess the appropriate code for the latched mode.

Thus, first and second embodiments of a dual-mode IC 11, smart card 10,system and associated method of operation in the ISO 7816 protocol andthe USB protocol have been described in accordance with the presentinvention. A medium, such as the smart card 10, incorporating thedual-mode IC 11, 51 can be used in a typical ISO compliant smart cardreader or in a lower-cost USB device, such as a personal computer 20.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims.

That which is claimed is:
 1. A dual-mode integrated circuit (IC) foroperating in an ISO mode in accordance with International StandardsOrganization 7816 (ISO 7816) protocol, and a USB mode in accordance witha Universal Serial Bus protocol, the dual-mode IC comprising: amicroprocessor; a switching block connected to the microprocessor; anexternal interface connected to the switching block and comprising avoltage supply pad, a reference voltage pad, a reset pad, a clock padand an input/output pad in accordance with the ISO 7816 protocol, and aD-plus pad and a D-minus pad in accordance with the USB protocol; and amode configuration circuit connected to the switching block forconfiguring the dual-mode IC in one of the ISO and USB modes based upona signal on at least one of the D-plus and D-minus pads.
 2. Thedual-mode IC according to claim 1 wherein the mode configuration circuitcomprises: a USB mode detector connected to at least the D-minus pad fordetecting a USB condition; and a latching circuit connected to theswitching block and receiving an output from the USB mode detector. 3.The dual-mode IC according to claim 2 wherein the mode configurationcircuit configures the dual-mode IC in the USB mode if a USB conditionis detected by the USB mode detector, and configures the dual-mode IC inthe ISO mode if a USB condition is not detected by the USB modedetector.
 4. The dual-mode IC according to claim 2 wherein the USB modedetector is also connected to the D-plus pad.
 5. The dual-mode ICaccording to claim 2 wherein the mode configuration circuit furthercomprises an ISO mode detector connected between the reset pad and thelatching circuit for detecting an ISO condition.
 6. The dual-mode ICaccording to claim 5 wherein the mode configuration circuit configuresthe dual-mode IC in the USB mode if a USB condition is detected by theUSB mode detector, and configures the dual-mode IC in the ISO mode if anISO condition is detected by the ISO mode detector.
 7. The dual-mode ICaccording to claim 2 further comprising a control register connected tothe latching circuit for storing a mode configuration indicator.
 8. Thedual-mode IC according to claim 2 further comprising a USB voltagedetector connected between the voltage supply pad and the latchingcircuit to detect a USB voltage supply.
 9. The dual-mode IC according toclaim 1 wherein the mode configuration circuit configures the dual-modeIC to operate in one of the ISO and USB modes while disabling the otherof the ISO and USB modes.
 10. The dual-mode IC according to claim 9wherein the reset, clock and input/output pads are disabled when thedual-mode IC is configured in the non-ISO mode, and the D-plus andD-minus pads are disabled when the dual-mode IC is configured in the ISOmode.
 11. A dual-mode smart card for operating in an ISO mode inaccordance with International Standards Organization 7816 (ISO 7816)protocol, and a USB mode in accordance with a Universal Serial Busprotocol, the dual-mode smart card comprising: a card body; and adual-mode integrated circuit (IC) carried by the card body andcomprising an external interface including a voltage supply pad, areference voltage pad, a first set of pads including a reset pad, aclock pad and an input/output pad in accordance with the ISO 7816protocol, and a second set of pads including a D-plus pad and a D-minuspad in accordance with the USB protocol, and a mode configurationcircuit for configuring the dual-mode IC in one of the ISO and USB modesand comprising a USB mode detector connected to at least the D-minus padfor detecting a USB condition, and a latching circuit connected to theUSB mode detector.
 12. The dual-mode smart card according to claim 11wherein the mode configuration circuit configures the dual-mode IC inthe USB mode if a USB condition is detected by the USB mode detector,and configures the dual-mode IC in the ISO mode if a USB condition isnot detected by the USB mode detector.
 13. The dual-mode smart cardaccording to claim 11 wherein the USB mode detector is also connected tothe D-plus pad.
 14. The dual-mode smart card according to claim 11wherein the dual mode IC further comprises an ISO mode detectorconnected between the reset pad and the latching circuit for detectingan ISO condition.
 15. The dual-mode smart card according to claim 14wherein the mode configuration circuit configures the dual-mode IC inthe USB mode if a USB condition is detected by the USB mode detector,and configures the dual-mode IC in the ISO mode if an ISO condition isdetected by the ISO mode detector.
 16. The dual-mode smart cardaccording to claim 11 wherein the dual-mode IC further comprises acontrol register connected to the latching circuit for storing a modeconfiguration indicator.
 17. The dual-mode smart card according to claim11 wherein the mode configuration circuit further comprises a USBvoltage detector connected between the voltage supply pad and thelatching circuit to detect a USB voltage supply.
 18. The dual-mode smartcard according to claim 11 wherein the mode configuration circuitconfigures the dual-mode IC to operate in one of the ISO and non-ISOmodes while disabling the other of the ISO and non-ISO modes.
 19. Thedual-mode smart card according to claim 18 wherein the reset, clock andinput/output pads are disabled when the dual-mode IC is configured inthe USB mode, and the D-plus and D-minus pads are disabled when thedual-mode IC is configured in the ISO mode.
 20. A dual-mode smart cardsystem for operating in an ISO mode in accordance with InternationalStandards Organization 7816 (ISO 7816) protocol, and a USB mode inaccordance with a Universal Serial Bus protocol, the dual-mode smartcard system comprising: a dual-mode smart card including a dual-modeintegrated circuit (IC) comprising an external interface including avoltage supply pad, a reference voltage pad, a reset pad, a clock padand an input/output pad in accordance with the ISO 7816 protocol, and aD-plus pad and a D-minus pad in accordance with the USB protocol, and amode configuration circuit for configuring the dual-mode IC in one ofthe ISO mode and the USB mode and comprising a USB mode detectorconnected to the D- minus pad, and a latching circuit connected to theUSB mode detector; at least one of an ISO-compliant smart card readerand a USB-compliant smart card reader for reading the dual-mode smartcard, the ISO-compliant smart card reader including an ISO interfacehaving a plurality of contacts for respectively mating with the voltagesupply pad, the reference voltage pad, the reset pad, the clock pad andthe input/output pad in accordance with the ISO 7816 protocol, and theUSB-compliant smart card reader including a USB interface having aplurality of contacts for respectively mating with the voltage supplypad, the reference voltage pad, the D-plus pad and the D-minus pad inaccordance with the USB protocol.
 21. The dual-mode smart card systemaccording to claim 20 wherein the mode configuration circuit configuresthe dual-mode IC in the USB mode if a USB condition is detected by theUSB mode detector, and configures the dual-mode IC in the ISO mode if aUSB condition is not detected by the USB mode detector.
 22. Thedual-mode smart card system according to claim 20 wherein the USB modedetector is also connected to the D-plus pad.
 23. The dual-mode smartcard system according to claim 20 wherein the mode configuration circuitfurther comprises an ISO mode detector connected between the reset padand the latching circuit for detecting an ISO condition.
 24. Thedual-mode smart card system according to claim 23 wherein the modeconfiguration circuit configures the dual-mode IC in the USB mode if aUSB condition is detected by the USB mode detector, and configures thedual-mode IC in the ISO mode if an ISO condition is detected by the ISOmode detector.
 25. The dual-mode smart card system according to claim 20wherein the mode configuration circuit further comprises a controlregister connected to the latching circuit for storing a modeconfiguration indicator.
 26. The dual-mode smart card system accordingto claim 20 wherein the mode configuration circuit further comprises aUSB voltage detector connected between the voltage supply pad and thelatching circuit to detect a USB voltage supply.
 27. The dual-mode smartcard system according to claim 20 wherein the mode configuration circuitconfigures the dual-mode IC to operate in one of the ISO and USB modeswhile disabling the other of the ISO and USB modes.
 28. The dual-modesmart card system according to claim 27 wherein the reset, clock andinput/output pads are disabled when the dual-mode IC is configured inthe USB mode, and the D-plus and D-minus pads are disabled when thedual-mode IC is configured in the ISO mode.
 29. A method of operating adual-mode integrated circuit (IC) in an ISO mode in accordance withInternational Standards Organization 7816 (ISO 7816) protocol, and a USBmode in accordance with a Universal Serial Bus protocol, the dual-modeIC including an external interface having a voltage supply pad, a firstset of pads including a reset pad, a clock pad and an input/output padin accordance with the ISO protocol, and a second set of pads includinga D-plus pad and a D-minus pad in accordance with the USB protocol, themethod comprising: detecting whether a USB-mode condition exists on atleast one pad of the second set of pads; configuring the dual-mode IC inone of the ISO mode and the USB mode based upon the detection; anddisabling one of the first and second set of pads based upon theconfiguration.
 30. The method according to claim 29 wherein detectingwhether the USB-mode condition exists on at least one pad of the secondset of pads comprises detecting whether the USB-mode condition existsduring a power-on-reset of the dual-mode IC.
 31. The method according toclaim 29 wherein detecting whether the USB-mode condition exists on atleast one pad of the second set of pads comprises detecting whether theUSB-mode condition exists on the D-minus pad.
 32. The method accordingto claim 29 wherein detecting whether the USB-mode condition exists onat least one pad of the second set of pads comprises detecting whetherthe USB-mode condition exists on the D-plus pad and the D-minus pad. 33.The method according to claim 29 wherein the dual-mode IC is configuredin the USB mode when the USB-mode condition is detected, and configuredin the ISO mode when the USB-mode condition is not detected.
 34. Themethod according to claim 29 further comprising detecting whether anISO-mode condition exists on one pad of the first set of pads during apower-on-reset of the dual-mode IC; wherein the dual-mode IC isconfigured in the USB mode upon the detection of the USB-mode condition,and configured in the ISO mode upon detection of the ISO-mode condition.35. The method according to claim 34 wherein detecting whether theISO-mode condition exists on one pad of the first set of pads comprisesdetecting whether the ISO-mode condition exists on the reset pad. 36.The method according to claim 29 further comprising verifying the USBmode, when the USB-mode condition is detected, by detecting a USB-modevoltage on the voltage supply pad.
 37. The method according to claim 29further comprising storing a mode configuration indicator for indicatingwhether the dual-mode IC is configured in the ISO or USB mode.